This invention relates generally to the field of photographic film processing, and more particularly to an improved means for transporting the strips of film to be developed through the several processing tanks of an automatic film developing machine.
Various arrangements are known for carrying out this film transporting.
One such arrangement involves strings of transport rollers, which are positioned along the generally sinusoidal path followed by the film through the various processing baths, and which are rotated to propel the film along its path. Typical arrangements of this type was disclosed in our U.S. Pat. Nos. 3,989,176 and 4,079,635.
Other arrangements are those disclosed in our prior U.S. Patent Applications Ser. No. 006,075 filed Jan. 24, 1979, and Ser. No. 016,390 filed Mar. 1, 1979. These use a tape attached to the edge of the film and extending lengthwise through the machine, generally parallel to and alongside of the film. This tape transports the film through the processing machine.
The foregoing arrangements are all eminently satisfactory for their intended purposes, but this does not mean that even they are not susceptible of further improvement.
Those arrangements which are disclosed in our prior issued patents require substantial numbers of transport rollers. This makes them somewhat complex, from the standpoint of both initial construction and subsequent maintenance. It also creates some possiblility, however slight, of marring the delicate emulsions which are present on the webs during processing.
Those arrangements which are disclosed in our still-pending prior patent applications utilize transport tapes which are positioned alongside the webs, as the latter are transported through the machine. When these webs are long (e.g. film strips 100 feet or more in length), the corresponding accompanying lengths of tape raise the cost of the processing operations. Moreover, the presence of web and tape side-by-side in the machine does create some slight possibility of mechanical interference by the tape with the unhindered processing of the web by the processing media within the machine.